[TAJO-1493] Make partition pruning based on catalog informations

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.12.0
• Component/s: Catalog, Planner/Optimizer
• Assignee: JaeHwa Jung
• Reporter: JaeHwa Jung
• Created: 01/Apr/15 01:47
• Updated: 02/Feb/16 07:52
• Resolved: 02/Feb/16 07:52

Description

Currently, PartitionedTableRewriter take a look into partition directories for rewriting filter conditions. It get all sub directories of table path because catalog doesn’t provide partition directories. But if there are lots of sub directories on HDFS, such as, more than 10,000 directories, it might be cause overload to NameNode. Thus, CatalogStore need to provide partition directories for specified filter conditions. I designed new method to CatalogStore as follows:

• method name: getPartitionsWithConditionFilters
• first parameter: database name
• second parameter: table name
• third parameter: where clause (included target column name and partition value)
• return values: List<org.apache.tajo.catalog.proto.CatalogProtos.TablePartitionProto>
• description: It scan right partition directories on CatalogStore with where caluse.
  For examples, users set parameters as following:
  • first parameter: default
  • second parameter: table1
  • third parameter: COLUMN_NAME = 'col1' AND PARTITION_VALUE = '3

In the previous cases, this method will create select clause as follows.

SELECT DISTINCT A.PATH
FROM PARTITIONS A, (
  SELECT B.PARTITION_ID
  FROM PARTITION_KEYS B
  WHERE B.PARTITION_ID > 0 
  AND (
    COLUMN_NAME = 'col1' AND PARTITION_VALUE = '3'
  )
) B
WHERE A.PARTITION_ID > 0
AND A.TID = ${table_id}
AND A.PARTITION_ID = B.PARTITION_ID

At the first time, I considered to use EvalNode instead of where clause. But I can’t use it because of recursive related problems between tajo-catalog module and tajo-plan module. So, I’ll implement utility class to convert EvalNode to SQL.

Issue Links

• is related to: TAJO-1952 Implement PartitionFileFragment
• is related to: TAJO-1441 Supporting INSERT (OVERWRITE) INTO for managed partitioned tables
• relates to: TAJO-1347 Apply column partitions to query optimizer.
• relates to: TAJO-1864 CatalogStore::getAllPartitions need to throw PartitionNotFoundException if there is no partitions on catalog.
• relates to: TAJO-1865 When building filtered partition path, check partition directory exists on filesystem.
• links to: filter writing rules of IMetaStoreClient::listPartitionsByFilter